Various types of downhole drilling tools including, but not limited to, rotary drill bits, reamers, core bits, and other downhole tools have been used to form wellbores in associated downhole formations. Examples of such rotary drill bits include, but are not limited to, fixed cutter drill bits, drag bits, polycrystalline diamond compact (PDC) drill bits, and matrix drill bits associated with forming oil and gas wells extending through one or more downhole formations. Fixed cutter drill bits such as a PDC bit may include multiple blades that each includes multiple cutting elements.
In typical drilling applications, a drill bit may be used in directional and horizontal drilling. Often in directional and horizontal drilling, the drill bit will drill vertically to a certain kickoff location where the drill bit will begin to curve into the formation, and at a certain point, the drill bit may begin horizontal drilling. One of the purposes of directional and horizontal drilling is to increase drainage of a reservoir into the wellbore and increase production from a well.
However, during directional and horizontal drilling, there may be an increased risk of unintentionally contacting or drilling into an existing well or other downhole obstruction that runs across the path of the drill bit. It may be difficult to determine when a drill bit impacts or is about to impact an existing well or other downhole obstruction. Further, it may be difficult to minimize damage to the drill bit or the existing well casing or liner upon unintentional contact. In other situations, it may be desirable to contact or drill into an existing well, such as drilling a relief well. In this case, it may be advantageous to determine when the drill bit is making contact with the existing well.